| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1996: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1995: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
Precipitation and aerosol samples were collected from April. 1995 to January. 1997 in Tsuruoka, Yamagata prefecture and anlyzed for chemical components.
We should like to probe for the characteristics of acid rain and snow at the coast of the Japan Sea and the origin of acidified matters in precipitaion and particulate atmospheric deposition (aerosols) on the investigated and obtained data.
As the result of considering, the following were mentioned ;
(1) The concentrationof the sea salt source ions (Na^+, Cl^-, Mg^<2+>, Ca^<2+>, and K^+) in precipitation and aerosol were higher value from winter to spring, than summer season for the reason that outburst of monsoon and seasonal wind from Asian continent had been strong from November to June, yearly.
(2) About soil source elements (Al, Fe and nss-Ca^<2+>), the concentration were higher in proportion to the strength of the west-wind with containing of loess and desert sand, caused Kosa phenomenon in spring.
(3) The acidifing mechanism of rainfall and snowfall might have been decided by the concentration ratio of acidified component such as [nss-SO_4^<2->] and [NO_3^-] to neutral component such as [NH_4^+] and [nss-Ca^<2+>].
(4) Non-sea-salt sulfate ion [nss-SO_4^2] in Tsuruoka were contained most large amount in aerosol samples and the concentraton measured at high value (4.6mug/m^3) throughout the year were more than twice as much as in Nishikawa, inland areas, Yamagata prefecture, and further, [nss-SO_4^2] becamed higher value when the sind had been blowing from the west than the east.
(5) The concentration of trace metals in precipitation and aerosol also were influenced by the wind directions, for instance, atmospheric Pb and Zn could be transported by the west-wind from continental cities and Sr were closely connected to desert soil from the Asian continent.
(6) Rainfall and Snowfall in Tsuruoka wre acid rain and acid snow at the rate of more than ninety percent and aerosols were all acid atmospheric deposition.
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